Owing to the excellent properties, such as corrosion resistance, ductility, and strength, titanium and titanium alloys are widely used as a material of aircrafts, golf clubs, and the like. In addition, due to the affinity to a living body, the materials are actively applied to a medical application, such as a dentistry application and an orthopedic application.
As described above, since titanium and titanium alloys have a wide variety of applications, a wide variety of processing techniques, such as, for example, cutting work and pressing work, are utilized for processing the materials. Particularly in recent years, as a processing technique for medical applications, methods for producing products and parts having different shapes and specifications on demand have increasingly been required.
As a technique for reproducing a desired shape on demand, a method in which a material is deposited to thereby form a three-dimensional shape (additive manufacturing technique) attracts attentions today, and 3D-printers which are three-dimensional printing processing apparatuses mainly using a polymer as a material are becoming popular.
As a material used for processing by a 3D-printer, aside from polymers, yttria-stabilized zirconia, pure copper, and hydroxyapatite are known (NPL 1). In addition, use of Ti-6Al-4V (64 titanium) as a material to be fed to a 3D-printer is also attempted (NPL 2).
However, NPL 1 does not disclose a processing technique using a titanium or titanium alloy powder as a material.
On the other hand, NPL 2 discloses a 3D metal lamination molding method using a Ti-6A1-4V alloy powder as a material, but only the average particle size is disclosed with respect to the shape and characteristics of the powder. NPL 2 focuses on the comparison between a metal powder laminated article produced by the 3D metal lamination molding method and a molded article produce by other methods (annealed article, rolled article), and there is disclosed no technical idea to reproduce an intended shape more precisely by controlling the shape and characteristics of the material alloy powder.
In addition, in light of experience of the inventors, when a general titanium or titanium alloy powder is used as a material to be fed to a 3D-printer, the shape collapses while a thin layer of the powder is-melt melted in a predetermined section, and a part or product having a desired shape can not be produced with high reproducibility in some cases. An improvement is demanded in this point.